Standard ground nepheline syenite in particulate form has been a commercial product for many years. Indeed, nepheline syenite powder in particulated form has been used extensively to make industrial compounds and to instill enhanced properties in liquid coatings, ceramics, glass, etc. For illustrations of representative products or compounds employing standard processed particulate nepheline syenite, the following United States patents are incorporated by reference. Consequently, the general properties and procedures for using existing nepheline syenite particles need not be repeated.
Koenig2,261,884use as flux in ceramicLyle2,262,951color ingredient in glassThiess2,478,645porcelain glazeHummel2,871,132glazing compoundHuffcut3,389,002heat and corrosion resistant coatingWeyand3,486,706binder for grinding agentWaters3,917,489ceramic fluxHarris3,998,624source of metal aluminum silicateBrown4,028,289inorganic fillerChastant4,130,423natural silicate for slag formationFunk4,183,760alumina ceramicAishima4,242,251alumina silicate fillerSeeney4,396,431inorganic binderDrolet4,468,473SiO2 sourceShoemaker4,639,576electrode coatingGoguen4,640,797polymer fillerVajs4,743,625vitrifying materialHolcombe5,066,330refractory fillerKohut5,153,155nonplastic fillerSlagter6,569,923polymer cementWhite6,790,904liquid coating
Disclosures contained in the patents listed above are incorporated by reference as background technology. Particulate nepheline syenite is used in diverse products and for many applications. However, the disclosed nepheline syenite powder does not have the total property array of the novel nepheline syenite powder constituting a first aspect of the invention. Furthermore, these background patents do not have or suggest the applications made available only by creation and use of the novel nepheline syenite powder. These novel products, with unique properties made possible by the newly developed, novel nepheline syenite powder, constitute a second or additional aspect of the inventive technology of this application.
Other uses of standard, ground nepheline syenite have been recently suggested. Representative examples of such newer applications of ground nepheline syenite are disclosed in the following United States patent publications:
Schneider2002/0137872scratch resistant coatingZarnoch2002/0173597filler in resin powderFenske2003/0056690filler for polymer cementBurnell2003/0085383suspending fillerBurnell2003/0085384heat curable resinWhite2003/0224174filler in liquid coatingScheider2003/0229157scratch resistant powder coatingGiles2004/0068048filler for rubberFinch2005/0059765filler for plastic coatingAdamo2005/0214534extender for curable compositionDuenckel2006/0081371sintering aidSchneider2006/0160930corrosion resistant coatingDorgan2006/0235113filler for polymer
These prior descriptions illustrate uses, or proposed uses, of ground nepheline syenite. Such additives have been used for many industrial components and as a filler, an extender or another component of consumer materials, such as coatings. However, the totality of this prior and extensive background technology has not led the mining industry to develop the novel nepheline syenite powder of the present invention or the uses of such novel nepheline syenite powder in both known and newly discovered applications. These new uses form novel products that are enhanced physically by use of ultra fine nepheline syenite powder having the characteristics of the novel form of nepheline syenite.
In addition to the background technology incorporated by reference in the section above, general background information regarding the use of ground nepheline syenite forms technical background to understand, practice and employ the present invention. In the glass and ceramic manufacturing industry, ground nepheline syenite provides alkalis that act as a flux to lower the melting temperature of a glass and/or ceramic mixture thereby promoting fast melting and fuel savings in the manufacturing process. In glass making, ground nepheline syenite also supplies aluminum which gives improved thermal endurance, increases chemical durability and increases resistance to scratching and breaking of the resulting vitrified product. Furthermore, ground nepheline syenite and larger grain nepheline syenite powder are used as a filler or extender in paints, coatings, plastics and paper. It is a desirable material because it contains virtually no free silica and still functions as effectively as a free silica based filler or extender. The material is an inorganic oxide having mechanical characteristics similar to the free silica materials for which it is used as a substitute in various industries. These mechanical properties of ground nepheline syenite are realized by the use of a fine grain particulate form of nepheline syenite, which is sometimes a powder that has a grain size greater than about 15-60 microns. These known ground and powdered nepheline syenite are quite abrasive for manufacturing equipment. Consequently the granular nepheline syenite has a high tendency to abrade and erode quite rapidly equipment used in processing the various compounds, even compounds incorporating the fine grain powder of the prior art. It has been determined that by reducing the fine grain size of any inorganic oxide material, such as nepheline syenite, the abrasive properties of the material are reduced. It is common to provide ground nepheline syenite with a relatively small grain size for the purpose of allowing effective dispersion of the product aided by the use of nepheline syenite powder. The advantage of dispersing fine grain nepheline syenite in the carrier product is discussed in several patents, such as Gundlach U.S. Pat. No. 5,380,356; Humphrey U.S. Pat. No. 5,530,057; Hermele U.S. Pat. No. 5,686,507; Broome U.S. Pat. No. 6,074,474; and, McCrary Publication No. US 2005/00019574. These representative patent publications show fine grain nepheline syenite and are incorporated by reference herein as background information regarding the present invention. These disclosures illustrate the advantages of providing this inorganic oxide in a very fine grain size for a variety of applications. In US Publication 2005/00019574 there is a discussion that microcrystalline silica is a preferred filler in plastic. Ground nepheline syenite from Unimin Corporation, New Canaan, Conn., is thus provided as a fine grain silica deficient silicate in the form of a sodium potassium alumino silicate. The particles of this nepheline syenite are finely divided and have a grain size in the range of about 2 to about 60 microns. This widely used commercial product having this grain size and wide particle size distributions has been sold as an additive that provides the nepheline syenite properties. Thus, materials employing ground nepheline syenite as a filler or extender and also as a glass or ceramic additive, has heretofore used fine grain nepheline syenite from Unimin Corporation having a controlled grain size less than about 60 microns. The produced nepheline syenite powder could not be produced with a controlled grain size of less than 15 microns. By using special equipment, Unimin Corporation has now been able to produce an ultra fine particle size nepheline syenite powder with a maximum particle size of less than about 10 microns; however, to make this material it is necessary to provide specialized grinding and milling equipment or drastically changed equipment operation. Consequently, in the past the standard, ground nepheline syenite used in various limited industries has been a nepheline syenite with a grain size controlled to be less than about 60 microns. In recent years, Unimin Corporation has developed a nepheline syenite powder which has a controlled grain size less than about 15 microns. This was believed to be the absolute industry limit for ultra fine nepheline syenite powder and forms the background. From experience, the industry believed that a limit of 15 microns was the ultimate grain size capability because the technology of producing nepheline syenite powder with controlled size less than 15 microns often involved moisture content which caused the particles to actually agglomerate into larger particles and defeat the primary purpose and cost of producing the smaller ultra fine particles. With respect to nepheline syenite powder, the terms “particle” and “grain” are used interchangeably. This is further background of the industry to which the present invention is directed.